GTP - Fixed Races - MGU?

Dipping my toes into GTP / Hypers.

Been running practice sessions and I’m able to run OK times in both the Porsche and Ferrari (2:03’s)

Realized tonight before registering for my first race in it, you’re not able to change the MGU/battery deploy map.

Trying to understand how people are driving the entire race without it fully depleting after 2-3 laps.

I’m assuming flat out is out of the question as it drains too quickly and I end up with 0%. Have been practicing trying to manage the battery but I just can’t seem to let it last.

Any tips would help!